Super Mega Renderer

I made this small mod to get usable high resolution images of blocks and items for minecraft videos.
Once the mod is installed, load a world and do

/renderexport [16 - 4096]

It will default to 512x512 if you leave the arg blank. The game will giga freeze for a time depending on how many textures need to get dumped. The result can be found in .minecraft/item_renders.